Many types of automated pipetting systems used for the aspiration and dispensing of relatively small quantities of liquids into the wells of plates such as microplates and apparatuses for cleaning wells are known in the art. Examples of liquids being dispensed include biological samples, solvents and reagents. Some or all of the liquid is normally drawn by suction through disposable pipette tips from one set of plates or a reservoir of sample and is released through the pipette tips into the wells of other plates. After use, the pipette tips are ejected and replaced with new ones and the sample containing wells are washed.
For example, U.S. Patent Application No. 2001/0039843 to Schoeppe discloses an automatic pipettor with a single row, multi-channel pipetting head and pipette tip ejector mechanism. The tip ejector mechanism includes a shaft oriented in the direction of a row of pipettes and push-off units fastened to the shaft in offset positions, each of which successively comes into contact with a strip-off unit guided in the direction of the pipettes during shaft rotation to strip tips.
U.S. Pat. No. 6,793,891 to Yiu discloses an automated pipetting and tip engagement and disengagement mechanism including a pipette block that engages pipettes and a locking plate system that engages pipette tips. The pipette block moves vertically with respect to the locking plate system to apply or decrease pressure within the pipette tip causing the pipette tip to dispense or aspirate fluid. When disengaging the pipette tips, the locking plate assembly holds the tips in place as the pipette block is lifted so that it travels sufficiently high to disengage the tips.
U.S. Pat. No. 6,734,683 to Hunicke-Smith et al. and U.S. Pat. No. 4,830,832 to Arpagus et al. also disclose automated pipetting apparatuses.
U.S. Pat. No. 7,220,384 to Muller discloses a washing and extracting head for an apparatus designed to wash microplates. The head is movable above the microplates and includes dispensing and suction tubes associated in pairs, the number of pairs being equal to the number of wells per row.
It is desirable to perform pipetting, tip ejection and washing operations rapidly and efficiently in a pipetting system.
An object of the present invention is to provide a new and improved apparatus or system for performing pipetting, pipette tip ejection and/or washing of sample wells.